import React, { Component } from 'react'
// 引入store，用于获取redux中保存状态
import store from '../../redux/store'

export default class Count extends Component {

  state = { carName: '奔驰c63'}

  /**
   * componentDidMount () {
   * // 检测redux中状态的变化，只要变化，就调用render
   * store.subscribe (() => {
   *  this.setState({})
   * })
   * }
   */

  //  加法
  increment = () => {
    const { value } = this.selectNumber
    store.dispatch({type: 'increment', data: value*1})
  }

  // 减法
  decrement = () => {
    const { value } = this.selectNumber
    store.dispatch({type: 'decrement', data: value*1})
  }

  // 奇数再加
  incrementIfOdd = () => {
    const { value } = this.selectNumber
    const count = store.getState()
    if (count %2 !== 0) {
      store.dispatch({type: 'increment', data: value*1})
    }
  }

  // 异步加
  incrementAsyc = () => {
    const { value } = this.selectNumber
    setTimeout(() => {
      store.dispatch({type: 'increment', data: value*1})
    }, 500);
  }

  render() {
    return (
      <div>
        <h1>当前求和为： {store.getState()}</h1>
        <select ref={e => this.selectNumber = e}>
          <option value="1">1</option>
          <option value="2">2</option>
          <option value="3">3</option>
        </select>&nbsp;
        <button onClick={this.increment}>+</button>&nbsp;
        <button onClick={this.decrement}>-</button>&nbsp;
        <button onClick={this.incrementIfOdd}>当前求和为奇数再加</button>&nbsp;
        <button onClick={this.incrementAsyc}>异步加</button>&nbsp;
      </div>
    )
  }
}
